Can't get an ip address. Network Control Block in use?

I've been using a win7rescuepe disc for a while in our office and its been working great. Recently I've been having a trouble getting an ip address from within the pe. Attempting to renew the ip address gives me this error:

"An error occurred while renewing interface Local Area Connection : The name specified in the Network Control Block (NCB) is in use on a remote adapter. The NCB is the data."

I haven't seen this error message before and don't really know what it means. As it indicates I suspect there is some sort of conflict with another computer on the network. If I plug this computer into it's own router with no other computers it gets an ip fine.
It's kind of hard to unplug other computers on the network without coming in early or on a day we're closed.
Anyone have any idea of what would cause this? I might try to reproduce the problem with a separate network on another router.

These are a couple of suggestions:
First for what I read you posted, there is a DHCP problem somewhere down the line.
Have you tried connecting the Win7PE computer Directly to the ISP box, and if you have a second network card use that one to connect to your home network (Private IP address manually assigned win PENetwork).
Other option is go to the PENework script in the middle section where it says: NETWORK PROFILES. Click on "Start Editor" and create a profile with the tabs: Identity (computer name, workgroup), and the tab: Network Adapter (select an adapter, and give an static IP, subnetmask, gateway, ISP DNS, etc. Lastly fill up the box to point to the newly created PENetwork profile. Create a new build and see if that works.